Spoon into prepared ramekins. Cover with the top circle. Put into a roasting pan with deep sides - I use a metal bread pan, and add hot water (hot tap water is fine) so that it comes half way up the sides of the ramekins. Bake in 400F (200C) oven for 30 minutes, until set - top will be firm.

Remove from oven and carefully remove ramekins from hot water.

Remove paper. Run a knife around edges of timbales and invert onto small plates. Remove paper.

Spoon Mushrooms on the side and serve.

Mushrooms

Chop onion; slice mushrooms.

Heat oil in a medium skillet. Add onions and sauté over high heat for 5 minutes.

Reduce heat to medium-low and sauté until very tender and starting to caramelize, about 15 minutes longer.

Add mushrooms and increase heat to medium. Sauté 5 minutes.

Add stock, mustard, heat until reduced and thickened.

Keep warm until needed.

Note: To clean butternut squash first peel it, using a potato/vegetable peeler. If it's large (typically) cut it in half between the 'neck' and 'bowl' ends. Then cut those in half the 'long' way. Scoop the seeds out of the round end and discard. I use the neck end for uniform pieces and the bowl end for soups and smaller pieces.